JP2667765B2 - Pneumatic tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of manufacturing a tire in which a gap is formed between an outer surface of a bead portion and a rim flange of a rim without leaking high pressure air in a tire bore when the tire is assembled to the rim. The present invention relates to a pneumatic tire that can maintain running stability of a tire by preventing rim displacement and stabilizing assembly accuracy after use.

[0002]

2. Description of the Related Art In a pneumatic tire, for example, a tire used for a passenger car, the frequency of sudden departure and sudden stop increases as the speed of the vehicle increases, and the tire is fitted with a rim with a strong fitting force. Is done. Also, in such high-speed running tires, so-called tubeless tires that do not use a tire tube have been increasingly used. In such a tubeless tire, the tire has a particularly strong fitting force and is fitted to a rim. Be worn. Also, for example, tires for buses and trucks to which a large load acts are fitted with a rim with a strong fitting force with an increase in the load.

[0003]

In assembling such a tire on a rim, as shown in FIG. 14, the bead bottom surface b of the bead portion a is strongly fitted to the rim sheet portion d of the rim c without any gap. However, the bead outer surface f guided by the rim flange e of the rim c is formed between the lower portion of the outer surface f and the flange e by the outer surface f being in close contact with the front end of the flange e at the time of rim assembly. A gap g is generated between them.

The gap g is gradually reduced as the tire runs and the outer surface f becomes more familiar.
As the gap g decreases, the rim assembling accuracy changes, the fitting state between the tire and the rim changes, and the balance of the initial rim assembling state and the distribution of force variations change. This worsens the imbalance and force variation. Further, since the contact area between the bead portion and the rim is reduced, the rim is displaced between the bead portion and the rim sheet when sudden braking is applied, which hinders straight traveling and reduces durability.

In the case of a rim-assembled tire, the aforementioned force variation is checked prior to shipment. However, there is a difference in assembling accuracy between a rim assembly in a factory and a rim assembly performed by a user himself. Exists. Therefore, in order to prevent the occurrence of the above-described force variation, it is necessary to provide a tire that does not have the above-described void even when the user assembles the rim without paying special attention.

[0006] The present inventors have conducted research and repeated experiments to satisfy the above-mentioned demands. (1) The closed gap between the bead outer surface and the rim flange generated at the time of rim assembly is reduced when the rim is assembled. In the above, there is provided an exhaust means capable of conducting the gap to the outside. (2) This exhaust means can be formed by providing a groove or a protrusion on the outer surface of the bead of the tire. (3) The exhaust means is provided with an inner end at a position radially away from the bottom surface of the bead by a certain distance. As a result, it has been found that the generation of the closed space between the outer side surface of the bead and the rim flange when the rim is assembled can be suppressed.

The provision of a ridge or groove on the outer surface of the bead has been proposed by Japanese Patent Publication No. 58-57321. However, this proposal is based on the fact that a tubeless tire has a rim diameter smaller than a design value on a wheel. The purpose is to prevent the tire from inflating when mounted, and in the above proposal, in order to achieve this purpose, the inner end of the groove or ridge extends close to the bead bottom surface. However, when the proposed configuration is adopted as the configuration of the present application for the purpose of removing a gap generated at the time of assembling the rim, there is a risk that even the air stored in the tire bore is discharged at the time of assembling the rim. Therefore, it has been found that it is necessary to keep the inner end position of the exhaust means at a distance from the bead bottom surface.

The present invention prevents the formation of a gap between the outer surface of the bead portion and the rim flange without leaking the high pressure air stored in the tire cavity when the tire is assembled on the rim. It is an object of the present invention to provide a pneumatic tire that can prevent rim displacement and prevent a change in rim assembling accuracy over time due to tire running, and can maintain running stability.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a pneumatic tire mounted on a regular rim, wherein a bead portion of the pneumatic tire has a bead outer surface facing a rim flange.
A bead base line and a separation point height Fh that is a distance in the tire radial direction between a separation point at which the bead outer surface of the tire correctly mounted on the regular rim is separated from the rim flange and 0.5 times or more, and the distance of 1.5 times or less of the bead portion and the rim flange when mounted to the bi <br/> over de from baseline tire extends radially outwardly from the inner end positioned within the region separating radially outwardly regular rim Rutotomo provided an exhaust means for forming an air passage for releasing air between
In addition, by filling the internal pressure,
The bead outer surface up to the inner end of the air means
Airtight that substantially abuts the
A pneumatic tire characterized by forming a contact portion .

Here, the bead base line is a reference for the nominal diameter NRD of the rim, and is a line in the tire axial direction passing through the intersection of the rim sheet and the rim flange.

The exhaust means may be a groove recessed on the outer surface of the bead, or may be a ridge projecting from the outer surface of the bead.

[0012]

Since the exhaust means having the above structure is provided on the outer surface of the bead, when the rim is assembled, the air interposed between the outer surface of the bead and the rim flange is reduced to air when the outer surface of the bead is brought closer to the rim flange. It can be discharged to the outside through the flow passage, and as shown in FIG. 14, air does not remain on the outer surface of the bead near the bottom of the bead. As a result,
Bead from the bead baseline to the inner end of the exhaust means
The outer surface substantially abuts the rim flange and is inside the tire.
An airtight contact can be formed to prevent air from flowing out of the cavity.

As a result, the nonuniformity of the accuracy of the rim assembly in the circumferential direction, which tends to be caused by the decrease of the air gap with the passage of time during the running of the tire, is reduced. Force variations due to RRO and imbalance are not increased. As a result, since the vibration does not increase even when the vehicle is driven for a long period of time, the driving stability and ride comfort can be maintained, and the tire bead and the rim can be uniformly fitted and abutted. Rim can be prevented at the time of sudden braking, and the durability can be enhanced. In addition, workability is not reduced without paying extra attention to the rim assembly work.

The exhaust means has a separation point height Fh which is a radial distance between the bead base line and the separation point.
A distance of 0.5 to 1.5 times the bead baseline
And extends radially outward from an inner end located in a region that is radially outwardly separated from the center.

At the time of assembling the rim, as shown in FIG. 15, the outer surface f of the bead portion is brought closer to the rim flange e by increasing the pressure p of the tire cavity, and a gap g formed between the outer surface f and the rim flange e. Is discharged through the exhaust means h. However, when the position of the inner end of the exhaust means is brought close to the bead bottom face b, the rim seat part e of the bead bottom face b and the rim c, for example, when the rim assembling work is started. If there is a poor fit between the two, there is a risk of air in the lumen leaking through the exhaust means.

Further, the gap g generated when the rim is assembled is
CT scanner according to a result of the observation, it tends to remain in the region close to the bead bottom surface b is confirmed, the complete removal of the gap g is necessary to contact the inner side portion near to the bead bottom surface b of the bead outer surface f There is. For this reason, the inner end of the exhaust means is restricted to 0.5 times the height Fh of the separation point. Further, it is preferable that the position of the inner end of the exhaust means is located outward in the radial direction as much as possible.

The reason why the position of the inner end of the exhaust means can be set to exceed 1.0 times the height Fh of the separation point is as follows. When assembling the rim, the bead bottom surface and the rim sheet are fitted with a strong fitting force. Therefore, at the start of the rim assembling, as shown in FIG. 8, the lower part of the bead portion is fitted into the rim in a posture inclined inward in the tire axial direction. Therefore, the bead outer surface comes into contact with the rim flange at an upper position exceeding the separation point height Fh, and the inner end of the exhaust means can be located outside the separation point height Fh. However, if the inner end position of the exhaust means is set to be more than 1.5 times the separation point height Fh, the inner end of the exhaust means does not conduct to the gap even when the rim assembly is started, and the air in the gap is discharged. There is no danger.

As described above, according to the present invention, the air gap between the bead outer surface and the rim flange generated at the time of assembling the rim can be eliminated by providing the bead outer surface with the exhaust means that regulates the region where the radial inner end is located. It is possible to improve the accuracy of the rim assembly, suppress fluctuations in the rim assembly accuracy over time due to tire running, maintain and stabilize running performance,
Moreover, it is possible to prevent the air in the tire cavity from leaking during the rim assembling work.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 8, the pneumatic tire 1 has a regular rim 1
A description will be given below in a normal state in which the normal internal pressure is set to 0 and the normal internal pressure is charged. In this embodiment, the pneumatic tire 1 is formed as a tubeless tire, and the bead portion 2 is formed on the bead outer surface 4 facing the rim flange 11 on the outer side in the tire axial direction, and in this embodiment, exhaust means 5 extending in the tire radial direction.
6A is provided.

The regular rim 10 is formed by erecting the rim flange 11 from the axially outer end of a bead base 12 on which the bead bottom surface 2a of the bead portion 2 is seated. Is attached.

The pneumatic tire 1 has sidewall portions 23 extending radially inward from both ends of a tread portion 22 and the bead portions 2 located radially inside the sidewall portion 23. A toroidal carcass 27 passing through the side wall portions 23, 23 and the tread portion 22 is bridged between the bead cores 26 provided in the bead portions 2, 2, and a radially outer and tread portion thereof is provided. A belt layer 29 is disposed inside the belt 22.

The carcass 27 is a so-called radial or semi-radial array in which carcass cords are arranged at an angle of 60 to 90 degrees with respect to the equator C of the tire in this embodiment. , Rayon, aromatic polyamide and the like.

The belt layer 29 is provided with belt cords which are arranged obliquely on the respective belt plies forming the belt layer 29 and intersect with each other. The belt cords, like the carcass 27, are made of nylon, polyester, rayon, A steel cord is used in addition to a fiber cord such as an aromatic polyamide.

Further, in this embodiment, a reinforcing layer 31 wrapping the carcass 27 is disposed in the bead portion 2, and the reinforcing layer 31 is formed by combining an organic fiber cord having strength such as steel cord or aromatic polyamide with the carcass cord of the carcass. The reinforcing layers 31 are formed into a sheet shape arranged side by side in a direction intersecting with each other, and the rigidity of the bead portion 2 is enhanced.

In the bead portion 2, a chafer 32 capable of forming a bead bottom surface 2a and a bead outer surface 4 is disposed outside the reinforcing layer 31. In this embodiment, the chafer 32 is formed.
The hardness of the rubber is higher than that of the other rubber of the tire bead portion 2, and the hardness is set to 65 degrees or more of the JISA hardness.

In the pneumatic tire 1, the bead bottom surface 2a is seated on the bead seat portion 12 of the regular rim 10 when the rim is assembled, and the bead outer surface 4 is in contact with the rim flange 11. The rim flange 11 is curved outward in the radial direction at the radially outer portion as shown in FIG. 2, and the bead outer surface 4 properly mounted on the regular rim 10 with the bead base line 7 as a starting point. The distance in the tire radial direction from the flange 11 to the separation point B separated from the flange 11 is defined as a separation point height Fh.

As described above, the bead outer surface 4 is provided with the groove 6A extending inward and outward in the radial direction. The groove 6A is
The inner end D is located in a region S which is separated from the bead base line 7 by a distance F not less than 0.5 times and not more than 1.5 times the height Fh of the separation point, and the groove 6A is located outward in the tire radial direction. It is stretched.

The bead outer surface 4 is provided with at least two, preferably eight or more, grooves 6A having the above-mentioned structure in the tire circumferential direction, and the width WA of the grooves 6A in the tire circumferential direction is 0.1 mm. 3 to 5.0 mm, preferably 0.5 to
In the range of 1.0 mm, the axial depth of the groove 6A, that is, the height HA is 0.5 to 2.0 mm, preferably 0.7 to 1.0 mm.
Is set in the range.

The function of exhausting the air in the gap g between the bead portion formed by the groove 6A and the rim flange will be described.
The operation of the groove 6A is slightly different depending on the range of the region S where the inner end D of the groove 6A is located. Each case will be described.

(1) As shown in FIG. 5, the inner end D of the groove 6A is separated from the bead base line 7 by a distance F1 of 0.5 to 0.8 times the separation point height Fh, and the outer end E is set at the separation point. When located near B. In the case where the rigidity of the bead portion 2 of the tire is large and the bead portion 2 is gently inclined as shown in FIG. Since the outer end of the groove 6A is located near the separation point D, the air in the gap g can be exhausted through the groove 6A even when the bead portion 2 has a gentle inclination as shown in FIG. Exhaust means 5 is provided which forms an air flow passage for releasing air in a gap g generated between the outer side surface 4 and the rim flange 11. Also, bead outer surface 4 and rim flange
By evacuating the air between the first and the second, as shown in FIG.
From the bead baseline 7 to the inner end D of the exhaust means 5
The outer side of the bead is substantially in contact with the rim flange 11
Forming an airtight contact portion 8 for preventing air from flowing out of the tire bore.
sell.

(2) As shown in FIG. 7, the inner end D of the groove 6A is separated from the bead base line 7 by a distance F2 which is more than 0.8 times the separation point height Fh and not more than 1.5 times the height Fh. When the outer end E is located at a position extending 5 to 15 mm radially outward from the end D. In the case where the bead portion 2 of the tire has a slightly soft bending rigidity and the rim is assembled in a state where the bead portion 2 is greatly inclined with respect to the radial line of the tire as shown in FIG. 11 is fitted into the regular rim 10 while being largely inclined with respect to the rim 11. Therefore, even if the inner end is at a position higher than the bead bottom surface 7, the air in the gap g can be exhausted through the groove 6A as shown in FIG. An exhaust means 5 for forming an air flow passage for releasing air is provided. Also outside the bead
Exhausting air between the side surface 4 and the rim flange 11
Exhaust from the bead baseline 7 as shown in FIG.
The outer surface of the bead up to the inner end D of the means 5 is the rim flan.
Substantially abuts the die 11 to prevent the air from flowing out of the tire bore
An airtight contact 8 can be formed.

(3) The position of the inner end D is defined as the separation point height Fh.
Even when it is set to be more than 1.0 times the inner diameter D of the groove 6A due to the bead portion 2 being greatly inclined during the rim assembling operation and being fitted into the normal rim, the rim flange 1
1 in the radial direction. As a result, when the rim assembly is completed, the rim assembling can be performed with high accuracy without the groove 6 </ b> A intervening between the bead outer surface 4 and the facing surface of the rim flange 11.

The groove width WA of the groove 6A is less than 0.3 mm;
Alternatively, when the groove depth HA is 0.3 mm or less, the rubber of the bead portion 2 is compressed and deformed by the contact between the bead outer surface 4 and the rim flange 11 during the rim assembling operation, and the air flow passage may be closed. On the other hand, the groove width WA exceeds 5.0 mm,
Alternatively, if the groove depth HA exceeds 2.0 mm, there is a risk that the strength of the bead portion 2 is reduced and the sealing effect is impaired. When the groove depth HA is 1.0 mm or less, the air formed by the groove 6B due to the elastic deformation due to the pressing of the bead portion 2 at the stage where the bead portion 2 is fitted into the regular rim 10 and the accurate rim assembly is completed. The flow passage is closed to prevent air from leaking into the tire lumen and further improve airtightness.

Further, in this embodiment, as shown in FIG. 3, by providing a bypass groove 9 extending in the tire circumferential direction radially inward of the separation point B between adjacent grooves 6A, 6A, the grooves 6A. And the uniformity of the rim assembling accuracy can be improved. The groove shape of the groove 6A can be set to various shapes such as a trapezoidal shape, a rectangular shape, and a truncated circular shape.

9 to 13 show another embodiment in which the exhaust means 5 is formed by the protrusion 6B. In this example, the bead outer surface 4 is provided with a ridge 6B extending inward and outward in the radial direction. The ridge 6B has its inner end D positioned in a region S separated from the bead base line 7 by a distance F of 0.5 to 1.5 times the separation point height Fh. 6B extends outward.

The bead outer surface 4 has the protrusion 6B
At least two, preferably 8 apart from each other in the tire circumferential direction.
The width WB of the ridge 6B in the tire circumferential direction is in the range of 0.3 to 5.0 mm, preferably 0.5 to 1.0 mm, and the height HB of the ridge 6B in the axial direction is 0. .3-2.
0 mm, preferably in the range of 0.5 to 1.0 mm.

By providing such a ridge 6B,
When the rim is assembled, the bead outer surface 4 is
Prior to contacting the inward surface of the ridge 1, the leading end of the ridge 6 </ b> B abuts the rim flange 11, and on both sides of the ridge 6 </ b> B, an air flow passage for releasing air between the bead portion 2 and the rim flange 11 is provided. The ridge 6B forms the exhaust means 5. Ma
In addition, the air between the bead outer surface 4 and the rim flange 11 is
By evacuating, as shown in FIG.
The bead outer surface from the in 7 to the inner end D of the exhaust means 5 is
The rim flange 11 is substantially in contact with the cavities of the tire bores.
An airtight contact portion 8 for preventing outflow of air can be formed.

When the height HB of the ridge 6B is set to 1.0 mm or less, when the rim is correctly assembled, the air circulation is performed for the same reason as when the groove depth HA is set to 1.0 mm. Since the road is closed, air leakage in the tire lumen can be prevented more reliably.

The ridge 6B may be integrally formed with the bead rubber forming the bead outer surface 4 as shown in FIG.
Further, as shown in FIG. 13, the ridge 6B is formed as a separate body from the bead outer surface, and when the bead portion 2 is rim-assembled to the regular rim, this separate ridge 6B is provided between the bead outer surface and the rim flange portion 11. The exhaust means 5 can also be formed by sandwiching the ridge 6B.

[0040]

[Examples] Tires having a tire size of 205 / 65R15 and having the configurations shown in FIGS. 1 and 2 (Examples 1 and 2)
The rim is assembled to a regular rim of 6.55JJ × 15,
Air gap g when assembling the rim under an internal pressure of 2.0 kg / cm ²
Was measured. As shown in FIG. 15, the rims were similarly assembled for the tire (comparative example) having the conventional structure in which the air vent groove was not provided, and the gaps were compared. The size of the gap was measured using a CT scanner.
In addition, the measurement of the voids is performed at each of four positions in each of the front set and the back set, and the average value is shown.

For the measurement of the rim deviation amount, the test tire is mounted on an actual vehicle, and the rim is run at a speed of 80 km / H and a brake is applied so that 0.8 G is applied by a gravitational accelerometer that measures acceleration in the traveling direction. After the braking test was repeated 20 times, the total amount of rim displacement between the tire and the rim was measured.

With respect to the state of occurrence of vibration, the presence or absence of vibration after traveling 100 km on an actual vehicle equipped with test tires was determined by driver's feeling. Table 1 shows the measurement results.

[0043]

[Table 1]

As a result of the test, as shown in Table 1, the air gap of the embodiment was smaller than that of the comparative example when the rim was assembled, and the outer surface of the bead was substantially in contact with the rim flange.
Are in contact, also it rim deviation amount it was able to confirm the occurrence of vibration after the lapse of a de minimis der Ri use was suppressed.

[0045]

As described above, the pneumatic tire of the present invention has the following features.
The distance from the outer side surface of the bead to the distance between the outer side surface of the bead and the separation point from the rim flange is 0.5 to 0.5
An exhaust means is provided which extends outward from an inner end located in a region radially outwardly separated from the bead base line by a distance of 1.5 times and allows air between the bead portion and the rim flange to be released when mounted on the regular rim. Air in the tire bore
It is possible to reduce the amount of voids generated between the outer surface of the bead and the rim flange when the rim is assembled without letting it out . As a result , the gap between the bead outer surface and the rim flange
By exhausting air, it is exhausted from the bead baseline.
The bead outer surface up to the inner end of the air means
Airtight that substantially abuts and prevents air from flowing out of the tire lumen
A contact portion is formed to reduce rim displacement during running to increase durability, suppress a change in accuracy of the rim assembly over time due to tire running, and maintain running stability for a long period of time, and It can also be used for tubed tires.

[Brief description of the drawings]

FIG. 1 is a right half sectional view of a tire showing one embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part thereof.

FIG. 3 is a front view showing a groove.

FIG. 4 is a tire circumferential direction sectional view showing a bead outer surface and a rim flange when a rim is assembled.

FIG. 5 is a sectional view showing an operation after the rim is assembled.

FIG. 6 is a cross-sectional view showing an operation in the process of assembling the rim.

FIG. 7 is a cross-sectional view showing an operation after the rim is assembled in another mode.

FIG. 8 is a cross-sectional view showing the operation of the rim during its assembly.

FIG. 9 is a right half sectional view of a tire showing another embodiment.

FIG. 10 is an enlarged sectional view showing a main part thereof.

FIG. 11 is a cross-sectional view of a ridge in a tire circumferential direction.

FIG. 12 is a cross-sectional view showing a bead outer surface and a rim flange when the rim is assembled.

FIG. 13 is a circumferential sectional view of a tire bead portion showing another example of the ridge.

FIG. 14 is a sectional view showing a conventional technique.

FIG. 15 is a cross-sectional view showing a conventional tire rim assembly.

[Explanation of symbols]

 2 bead part 4 bead outer surface 5 exhaust means 6A groove 6B ridge 7 bead bottom surface 10 regular rim 11 rim flange B separation point D inner end E outer end F1, F2 distance Fh separation point height HA, HB height S area WA , WB width

 ────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-59-149802 (JP, A) JP-A-2-270610 (JP, A) JP-A-54-100004 (JP, A) Actual development Sho-52- 32803 (JP, U) JP 58-57321 (JP, B2)

Claims (12)

(57) [Claims] 1. A pneumatic tire mounted on a regular rim, comprising: a bead base line on a bead outside surface where a bead portion of the pneumatic tire faces a rim flange; and a tire correctly mounted on the regular rim. radial tire radial distance a is the distance of 0.5 times or more and 1.5 times or less of spaced points height Fh of between spaced points where the bead outer surface separates from the rim flange from the bead base line Rutotomoni provided an exhaust means for forming an air passage for releasing air between the bead portion and the rim flange during mounting from the end to the tire normal rim extends radially outwardly among positioned within the region that separates the outside, By filling the internal pressure, the exhaust
The outer bead surface up to the inner edge of the step is
Airtight contact that qualitatively abuts and prevents air from escaping the tire bore
Forming a pneumatic tire. 2. The pneumatic tire according to claim 1, wherein said exhaust means comprises a plurality of grooves formed in the outer surface of the bead. 3. The exhaust means comprises a plurality of ridges protruding from an outer surface of the bead.
The pneumatic tire as described. 4. The exhaust means further comprises an inner end extending radially outward from the bead base line by a distance of 0.5 to 0.8 times the separation point height Fh and an outer end extending further radially outward. The pneumatic tire according to claim 1, 2 or 3, which comprises a groove or a ridge located near the separation point. 5. The exhaust means further extends radially outward from an inner end which is separated from the bead base line radially outward by a distance exceeding 0.8 times and not more than 1.5 times the separation point height Fh. The pneumatic tire according to claim 1, 2 or 3, wherein the pneumatic tire extends from 5 to 15 mm. 6. The exhaust means is disposed radially outward from an inner end separating the bead baseline by a distance exceeding 1.0 times and not more than 1.5 times the separation point height Fh. 3. The method according to claim 1, wherein the object extends from about 15 mm.
Or the pneumatic tire according to 3. 7. The exhaust means comprises at least two grooves or ridges provided in a circumferential direction of the tire.
The pneumatic tire as described. 8. The exhaust means comprises eight or more grooves or ridges provided at intervals in the tire circumferential direction.
The pneumatic tire as described. 9. The exhaust means has a width in the tire circumferential direction of 0.1 mm.
The pneumatic tire according to claim 1, 2 or 3, wherein the pneumatic tire comprises a groove or a protrusion having a length of 3 to 5.0 mm. 10. The pneumatic tire according to claim 1, wherein said exhaust means comprises a groove or a ridge having a width in the tire circumferential direction of 0.5 to 1.0 mm. 11. The pneumatic tire according to claim 1, wherein said exhaust means comprises a groove or a ridge having a height in the tire axial direction of 0.5 to 2.0 mm. 12. The pneumatic tire according to claim 1, wherein said exhaust means comprises a groove or a ridge having a height in the tire axial direction of 0.7 to 1.0 mm.